All you need for GRE you can find here on this blog, lots of material for Quantitative, Verbal and Analytical Writing sections.
Everything sorted in such way that is best for quick and successful studying.

Paragraph 1: - Demonstrate that the Argument is understood - List weaknesses. Most fall into these two categories: Fails to validate assumptions, uses poorly defined terms. - Mention what could be done to strengthen the Argument.

Paragraph 2: - Detail assumptions upon which the Argument hinges - Describe what would be required to validate these assumptions (consider expert testimony, empirical research, and real-life examples) - List gaps between existing evidence and what is necessary

Paragraph 3: - Discuss poorly defined terms. What could they mean? How would these different meanings affect the Argument?

Final Paragraph: - Discuss what could strengthen the Argument - Summarize the essay.